Mendoza G D, Britton R A, Stock R A
Department of Animal Science, University of Nebraska, Lincoln 68583-0908.
J Anim Sci. 1993 Jun;71(6):1572-8. doi: 10.2527/1993.7161572x.
Eight ruminally, duodenally, and ileally fistulated sheep were used to study the effects of protozoa on ruminal fermentation and starch digestion in the rumen and intestines. The experimental diet (75% grain DM basis) was based on a mixture of 67% high-moisture corn (HMC) and 33% dry-rolled grain sorghum (DRGS). Protozoa were reduced from 51,286 to 13,987 organisms/mL of ruminal fluid by feeding a diet (13 d) containing 9% tallow and monensin at 27 mg/kg (DM basis). Three sheep were defaunated by intraruminal infusions of lactic acid (20 to 30 g/d) and one sheep by washing the rumen and heating ruminal contents (60 degrees C for 20 min). No differences were observed in DM or starch intake, ruminal fluid pH, lactate concentration, or total tract starch digestibility. Molar proportion of acetate was reduced (48.6 vs 58.3%; P < .01) and propionate was increased (32.2 vs 23.4%; P < .03) by defaunation. Total VFA tended (P = .20) to be lower in faunated sheep (118.5 vs 139.2 mM). In situ rate of starch digestion of HMC (22.3 vs 14.7 %/h; P < .02) and DRGS (5.1 vs 3.3 %/h; P < .009) was increased by defaunation. Starch digestibility (percentage of intake) in the rumen was increased (P < .001) by defaunation (84.2 vs 93.7%) and was reduced (P < .002) in the small intestine (5.2 vs 13.6%). Defaunation increased (P < .03) amylolytic activity (.40 vs .17 units/mg of protein; P < .03) and osmotic pressure (321 vs 245 mOsm/kg; P < .006).(ABSTRACT TRUNCATED AT 250 WORDS)
选用八只瘤胃、十二指肠和回肠造瘘的绵羊，研究原生动物对瘤胃发酵以及瘤胃和肠道中淀粉消化的影响。实验日粮（以75%谷物干物质为基础）由67%的高水分玉米（HMC）和33%的干压碎谷物高粱（DRGS）混合而成。通过饲喂含9%牛脂和27毫克/千克（干物质基础）莫能菌素的日粮（13天），将瘤胃液中原生动物数量从51,286个/毫升降至13,987个/毫升。三只绵羊通过瘤胃内注入乳酸（20至30克/天）进行去原虫处理，一只绵羊通过冲洗瘤胃并加热瘤胃内容物（60摄氏度，20分钟）进行去原虫处理。在干物质或淀粉摄入量、瘤胃液pH值、乳酸浓度或全消化道淀粉消化率方面未观察到差异。去原虫处理使乙酸的摩尔比例降低（48.6%对58.3%；P <.01），丙酸比例增加（32.2%对23.4%；P <.03）。去原虫处理的绵羊中总挥发性脂肪酸含量有降低趋势（P = .20）（118.5对139.2毫摩尔）。去原虫处理使HMC的淀粉原位消化率提高（22.3%对14.7%/小时；P <.02），DRGS的淀粉原位消化率也提高（5.1%对3.3%/小时；P <.009）。去原虫处理使瘤胃中淀粉消化率（摄入量的百分比）提高（P <.001）（84.2%对93.7%），而在小肠中降低（P <.002）（5.2%对13.6%）。去原虫处理使淀粉酶活性提高（P <.03）（.40对.17单位/毫克蛋白质；P <.03），渗透压升高（321对245毫渗量/千克；P <.006）。（摘要截断于250字）
